Paper bags



`uly 16, 1957 Filed March 17, 1953 F. I UHRMANN ETALv PAPER-BAGS 2 Sheets-Sheet l July 16, 1957 F. LHRMANN ET AL 2,799,443

' PAPER BAGS Filed March 17, 1951 2 Sheets-Sheet 2 www@ Unit@ PAPER BAGS Fritz Liihrmann, Lengerich, and Ernst Klein, Hoste, near Lengerich, Germany, assignors to Bischoff & Klein, Lengerich, Westphalia, Germany, a German corporation Application March 17, 1951, Serial N o. 216,128 I Claims. (Cl. 229-60) s atef at only one end of the bag tube when an open bag is being manufactured.

Bag bottoms are formed by first turning7 4over and folding the bag bottom flaps and then closing the bag bottom by turning over its side flaps.

The finished paper bags manufactured in this manner have crease folds in their bag bottom corner flapscaused by the longitudinal folding in the formation of the bag tubes since the tubes are folded over their over-all length.

Due to thesecrease folds in the bag bottom corner aps the finished bag bottoms have so-called air channels which allow leakage of material which is packed in the bag. This is particularly true when the bag is filled with powder or granular materials since this material .I

especially great at the upper corner of the bag opposite J the bag valve and material may easily escape from this portion.

These air channels in the corner flaps of the bagbottom are greatly increased because the crease foldsy in the corner iiaps of the bag bottom bulge outwhen the bag f.

bottom is closed by the turning over of* its side flaps so that the corner flaps of the bag bottomV do not lie smooth when they are pasted with the bag bottom side flaps andy retain their uneven positionv even after they are formedl into` finished bag bottoms. 'bags are constructed from paper consisting of several layers, these crease folds are particularly disadvantageous because theyvcause great unevenness in the corner flaps of the bag bottom and thus bring about the aforementioned leaks. j

One object of this invention is a paper bag without the aforementioned disadvantages. Y

A further object of this invention isv a blank which When the paper may easily be folded into an improved paper bag. This and further objects will becomeapparent from the fol- Fig. 5 is the piece of paper which is developed in al Patented July 16, 1957 f. ICC

tube shape in the vicinity of the bag wall to be formed showing the spread-open bottom parts of the bag;

Fig. 6 is the paper bag with its bottom still open;

Fig. 7 shows a perspective of a bag tube folded on both sides; v

Fig. 8 shows atop elevation of the bag tube of Fig. 1 with bag bottom corner flaps which have crease folds` causedrby the longitudinal folding of the bag tube; fFig. v9` shows diagrammatically the bulging out of the crease folds inthe corner flaps of the bag bottom upon the folding over of the bottom side flaps, on an enlarged scale@ v Y Fig. 10 shows paper bag tube formed according tothe invention.

Fig. 11 shows the tube shown inFig. l0 with the bag bottom corner flaps which do not have any crease fold;

and Y v Fig. 12 shows a finished Valve bag, the corner liaps of which are'fr'eefrom crease folds.

In accordance with the invention a paper bag is formed in which thetcorner aps of the bag bottom are so developed that Ithey `.do not have any crease folds caused by thelongitudinal folding `or scoring of the bag tube.

`The paper bag is formed from a blank Vwhich has predetermined bag fold` lines for forming a bag 2. These lines extend yonly over the length which is to be the bag wall portionand dol not extend to the bag bottom portion. When the bag 2 is formedv `from this blank, the bag bottom portion automatically spreads open'andv may be easily combined to form the bag bottom.

, With this new blank,.paper bags can be manufactured much more simply and rapidly than was heretofore known, inasmuch as now it is n ot necessary to first of ,allform a bag tube ofthe known kind, the gluing seam ,of which must be dry before the bottoms can be formed. Also, the opening of the bag tube ends', in order to form the'bottom, -is no longer necessary Vso that the complicated devices 4formerly used 'for this purpose, vfor eXamplesuction devices, are no longer needed. In addition to this, the bag bottom ends, in accordance with the newinethod, are spreadra'part much more uniformly than inaccordance with the oldwmethod so that the finished bag bottoms are Vmuch more uniform in appearance than those previouslyv made,y and finally the corner folds of thebag 'bottoms no longer receive bent lines during the formation 0f the bag tubes which, when produced in accordance with the known methods, appear in their center, and run parallel to the folding lines of the bottom side flaps and weaken thelbagrwall there and at the bag. ends.

for theformation lof a paper bag, is provided on both sides 'with both an individual longitudinal folding line 2 and 'a longitudinal folding line 3. VBetween the two folding lines 2, there extend the transverse folding lines 4. At'points 5, theA transverse folding lines 4 come against the longitudinal folding lines 2. From pointsS, bottom folding lines @branch-out. `All vof these Abag folding Ylines arevscor'efd'in accordance with the folding process, 1i. 1e.thef scores are provided in the manner that they favor' thetu'rning vover of the `individual bag parts fin theirV pertinent direction `of bend vduring the bag folding, asc'an be seen diagrammatically in Figs." 2 'and` 3.

If lthe piece of paper 1 during the scoring is` pressed in, in the direction of the. small straight arrow 7, .the direc'- vtionfof bend then lies' in theA direction of the a'rcshaped arrows .8fs`o'that` the. foldingprocedurerin the direction 0f 'these arrows 8, isfajciltadf "Durinsthe folding 0f .the

' bag; the individual" parts of th bag which 'a'reto'fbe folded over are easily folded over in the directions indicated by the arrows.

The form of the scores can be varied; for example,

they can be developed in the manner shown in Fig, 4

Referringfpto Fig. 1 of the drawing, the paper 1 serving` in the drawing. The form of the scores is selected to fit each individual case, depending on the strength of the piece of paper serving for the formation of the paper bag and also depending upon thenature of the material which is to be used for the manufactureof the bag. -The piece of paper 1 serving for the formation of the paper bag, may consist as is known of several layers, the edges of which can be staggered with respect to each other.

The scored piece of paper lies then formed in the region of the bag wall whichis to Abe formed into the shape of a at tube as can be noted from Figure 5 of the drawing. Parts 9 and 10 of the piece of paper 1 are only grasped inthe region lying between the longitudinal folding lines 2, folded along the transverse fold lines '4 and pasted together inthe vknown manner.

By the folding of parts 9 and 10, are the bag bottom parts 11 produced which spread open by themselves so that it is unnecessary rto open these parts by a special operation in the 'formation of the bottom.

'Ihe spread bag bottom parts 11 can easily be combined with each other to form bag bottoms, inasmuch as it is generally not ditl'lcult to fold the bottom aps 13 and 14 over, along the folding lines 3, even if the corner llaps 15 are not scored along folding lines 16. If, however, the piece of paper 1 serving for the formation of the paper bag is particularly diicult to bend, as for example, when it consists of several layers, it should in such cases also be scored along the folding lines 16 so that the corner flaps 15 do not offer any appreciable resistance to the turning over of side aps 13 and 14. The short paths 17 of folding lines 3 also need not be scored if the paper is easily folded over.

Referring to Fig. 7, a bag tube 21, as conventionally used in the manufacture of paper bags, is shown. The tube has the crease folds 31 and 41 over its entire length a.

If the bottom corner flaps 6 as shown in Fig. 8 are formed on the ends 51, 51 of this bag tube 21 in order to form a bag bottom, each of these bag bottom corner aps has a crease fold 71. Upon further formation of the bag bottom the bag bottom side aps 81 are turned over along `the scored lines 91 so as to close the bag bottom.

In this process the crease folds assume a bulged out position as shown in an enlarged scale in Fig. 9 in the direction of the arrow 101. On both sides of the crease fold 71 air channels 111 are produced. These air channels derive their name because air escapes out through them carrying along some of the material with which the bag is lled.

Fig. 10 shows a bottom tube formed according to the invention. The folded together tube 121 has folds extending along its longitudinal length over the distance b'. The corner flaps 131 which must be turned over to form the bag bottom are not folded nor scored so that they do not have any crease folds after they have been scored in the manner shown in Fig. ll. The nished valve bag shown in Fig. 12 thus does not have any crease folds caused by the longitudinal folding or scoring of the bag 21.

If the piece of paper 121 is formed so as to produce an open bag, it is folded on both sides over a distance c (as shown in Fig.r 4) so that the bag bottom corner aps are without creases at the end where the bag bottom is to be formed.

By forming the corner aps of the bag bottoms without any crease folds these flaps remain smooth andlose theirvtendency to bulge out on the turning over of the side flaps of the bag bottom and no disadvantageous air channels are formed. Thus the gluedY finished bag corners and the paperbags are tighter and stronger.

The bag is formed according to the invention by forming a bag -tube which is scored and folded in the bag body portion, but has no scores or fold marks at the portion which is to become the bag bottom.

It can thus be seen that the invention lies in a paper bag and a blank for forming the same in which the longitudinal folds for forming the paper bag tube do not extend through the bag bottom but only extend to where the bag bottom corner flaps will be formed If the bag tube is formed by rst scoring the paper and then folding it, the score marks should only extend this distance.

We claim:

1. A blank foldable into a paper bag which comprises at least one substantially rectangular sheet of paper dening a bag wall portion and at least one terminal bag end portion and two first folding lines established by scoring the paper on said bag wall portion of such paper terminating at the beginning of said terminal bag end portions, said rst folding lines being positioned so that the shortest distance between said rst folding lines at any point is less than the sum of the shortest distances between each said first folding line and the closest respective paper edge thereto.

2. Blank according to claim 1 in which at least one 2nd folding line is established by scoring the paper, said 2nd folding line being in said bag bottom portion and positioned to run at substantially right angles to said first folding lines.

3. Blank according to claim 2 in which at least one pair of 3rd and 4th, and at least one pair of 5th and 6th folding linesV are established by scoring the paper, said 3rd and 4th folding lines contacting each other at an angle, of about therebetween, said contact occurring at at least one end of one of said rst folding lines, said 3rd and 4th folding lines, being positioned to contact the closest edge of such paper in the direction of said first folding line, thereby forming a substantially isosceles triangle with the said edge of such paper, said paper edge being the hypothenuse of said triangle, said 5th and 6th folding lines contacting each other at an angle of about 90 therebetween, said contact occurring at at least one of the corresponding ends of the other of said first folding lines, said 5th and 6th folding lines being positioned to contact the same edge of such paper as said corresponding 3rd and 4th folding lines, thereby forming a substantially isosceles triangle with the said edge of such paper, said edge being the hypothenuse thereof.

4. Blank according to claim 3 in which there is established by scoring the paper at least one 7th folding line, said 7th folding line passing through the entire width of the paper being positioned to fold such paper in the opposite direction to said other folding lines, and to contact both said rst folding lines at the same ends thereof.

5. Blank according to claim 4 in which there are included additional folding lines established by scoring the paper positioned within said triangles at the shortest distance between the contact points of said 3rd, 4th, 5th and 6th folding lines with said 2nd folding line, and the nearest edge of such paper, said additional folding lines being positioned to fold such paper in substantially the same direction as said 7th folding line.

References Cited in the file of this patent 

